#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>

int main() {
    int a = 0, b = 0, c = 0, d = 0;
    scanf("%d %d %d %d", &a, &b, &c, &d);
    float sum = 0;
    sum = 0.2 * a + 0.1 * b + 0.2 * c + 0.5 * d;
    printf("%.1f", sum);
    return 0;
}